Around autumn last year, some observant friends had noted that I had stopped having desserts at the end of dinners and also generally declined sugar with the coffee. When asked, my response was the year-end festivities will commence soon and the body needed to be prepared for the dietary tsunami heading its way. And to a more or less large extent, that is perfectly true. What I don’t mention is that I am secretly enjoying cutting down on sugars and calories – and I don’t say this openly because many people would think I am kidding or somehow making fun of their dietary habits (which are somewhat unrestrained as mine used to be).
It should be stated that dieting does not come naturally to someone like me. I like eating gourmet food, I like cooking good food and I like the science of food. If the natural habitat of a lion is the plains of Africa, my natural habitat would be a good restaurant or a well-equipped kitchen with a nice dining bar.
So what motivated my dietary aspirations was a conversation with a scientist who casually asked one evening why I hadn’t yet written an article about Type 3 diabetes.
An intriguing chat ensued and it turned out that Type 3 diabetes is the name by which many scientists now call Alzheimer’s disease (AD).
To put it very simply, AD is considered to be the expression of diabetes in the brain. Evidence has been building for the relationship between AD and Type 2 diabetes (T2D) for many years.
For example, AD is twice as likely for patients suffering from T2D, and amyloids typically found in the defective organs of a T2D patient have many similarities to the amyloids found in the brains of AD victims. Amyloids are insoluble fibrous protein aggregates of improperly folded proteins and polypeptides.
Some research had suggested strongly that the brain itself produces insulin but this has yet to be conclusively validated. Insulin is one of the rare hormones that can cross the Blood-Brain Barrier (BBB) – that is, it can be transported across the normal blood circulatory system into the brain, and therefore insulin found in the Central Nervous System (CNS) may have originated from the pancreas.
However, the expected amount of insulin crossing the BBB does not tally with the higher total amount found in various parts of the CNS – hence the premise about the brain’s ability to produce its own insulin.
What is not in doubt is that there are several neural receptors for insulin and insulin is a crucial hormone for the proper functioning of the brain. Although brain cells tend to process insulin somewhat differently from other parts of the body, it has been conclusively demonstrated that the brain can develop insulin tolerance – and one end result of this appears to be AD. In the body, insulin tolerance (or resistance to the effect of insulin) is a cause of T2D and hence the reason why many scientists now refer to AD as Type 3 diabetes.
Saying that, there is a caveat – not all patients with AD have T2D and not all T2D patients get AD.
This anomaly might be explained by the fact that insulin is handled differently in the brain than the body. For example, insulin signalling is involved in a variety of neuron functions and the disruption of this signalling may lead to the development of AD. Another antecedent of AD may be the excess of glucose in the brain (a condition of diabetes) causing an increase in the levels of a compound called beta-amyloid peptide – this compound is a neurotoxin which may be another cause of AD. In short, there may be several causes of AD – and it would seem that in many cases, diabetic conditions in the brain had been involved.
Back to dieting
As both AD and T2D are more common in overweight people and linked to sugar consumption, the new-found understanding of diabetes was sobering enough to a man of my girth and dietary habits to revisit some general objections to dieting.
The main thing to remember is that I am not a dietician, I have no medical qualifications and the following dietary suggestions are based on logical analysis of currently known facts – done much in the same way as I would process facts or statistics at work.
So even though I use it personally, please don’t follow my diet – this story is purely for your entertainment, although it may help you elect a suitable diet one day if you are so inclined.
Much of the data presented below is extrapolated from websites that provide suggested values for raw calorie numbers – and therefore may be subject to some source errors but the dietary principles are still reasonably sound, in my opinion.
The unequal calories
Some basic dietary facts need to be cleared up first. One is that not all food calories are equal – a lot depends on how the food had been prepared (or cooked) before ingestion. Foods which are easier to digest obviously need less processing by the digestive system. As an example, the calories from a cooked carrot are more likely to find its way to your waistline than the calories from a raw carrot.
Since the middle of the last century, something called the Thermic Effect of Food (TEF) had already been investigated – this is the cost in calories from the effort needed to chew, digest, absorb and dispose of food eaten.
The TEF is also known as Dietary-Induced Thermogenesis (DIT) which is defined as the increment of energy expenditure above the resting metabolic rate due to the cost of processing food.
It also explains why many calorie-counting diets do not work. For example, a person dieting on cooked foods would always absorb more calories than another person dieting on the raw versions of the same foods, and hence the weight loss effect is completely different between them even though they are both eating the same amount of calories – the TEF is really that significant.
Additionally, some food classes are much easier to process than others:
• Sugars lose only 5% or less of their calorific value during food assimilation. This includes common carbohydrates such as amylopectin (such as that found in jasmine rice and white flour) and other refined carbohydrates. Glucose loses hardly any of its calorific value.
• Other carbohydrates such as wholemeal grains can require up to 15% of their calorific value to cover DIT. Fibrous carbohydrates such as certain vegetables (eg. broccoli, asparagus, legumes, kale, etc) can lose up to 20% of their calorific value due to TEF.
• Fats require between 5 to 15% of their calories to cover their thermic effect although it had been suggested that some medium-chain fatty acids (MCFAs) can raise the DIT by some 50%. These MCFAs can be found in coconut oil and, oddly, the fat in goat milk.
• Proteins have the highest thermic effect, requiring the loss of 20-35% of their calories during food assimilation – this is particularly pleasing as I like meat a lot.
So from the above, one can see that there will be a substantial difference in absorbed calories between someone eating 2,000 calories of white bread with jam (around 1,900 calories absorbed), and someone else chewing on 2,000 calories of rare lean steak (around 1,400 calories absorbed).
Your gut feeling
The other thing to consider is the effect of food on gut flora – ie the microflora in the intestines of the body. This gut microbiota is so crucial to health that it may be considered as a special virtual organ within the body and it is critical to maintain the health of intestinal flora – examples of its usefulness include the promotion of a good immune system, synthesising vitamins, building defences against allergies, general enhancement of the absorption of food nutrients, etc.
Breakfasts don’t matter
Contrary to much advice, studies have indicated that breakfasts do not mean much in the context of a balanced daily eating pattern. However, some people need an energy boost in the morning while others, like me, studiously avoid breakfast.
Studies have shown that the daily eating pattern does not really matter that significantly – having only a huge lunch and skipping dinner is perfectly fine, eating three times or more a day is also fine.
Even the type of food does not matter – for example, the notion of having sweetened cereals for breakfast is a relatively recent invention which started only around the 1920s, and since then has probably suited the cereal companies’ pockets more than your body.
So you should settle on a comfortable eating pattern (or no dining pattern at all) – but always be aware of your daily calorie requirement. If you need it, there are many websites that can help you track your daily calorie consumption but it is just as easy to use a spreadsheet on your phone if you already know the foods that you generally enjoy eating.
Naff targets and proposed new targets
One other noteworthy comment is that the daily dietary targets usually suggested for men and women are pretty naff. The general recommended target for men is 2,500 calories a day and women around 2,000 calories a day. This may be fine if you are a six-foot Caucasian man who jogs 5km a day but most people are either rather less statuesque or don’t jog so much – or in my case, both.
A rough approximation of how many calories you actually need may be calculated quite simply based on your height in centimetres and your age, using a simple table which I have devised. If you are, say, 170cm in height, then you can work out your daily requirement from the following:
Start by calculating the base calories for your height. To obtain this, simply multiply your height in cm by 10. So 170cm x 10 = 1,700 base calories.
Add the following to the base calories depending on your age:
So a 30-year old man with a height of 170cm should need 1,700 + 130 = 1,830 calories daily while a 30-year old woman of the same height should require roughly 1700 – 220 = 1,480 calories a day.
In the table, note that there are a few basic assumptions built in, which are: (i) the person is already a little overweight, (ii) the person is also actively moving around in an upright fashion for 20-30 minutes a day (eg. walking), and (iii) the person does not mind losing weight pretty gradually – but these are pretty reasonable expectations if someone is thinking about going on a diet.
Oh, just in case you’re thinking about losing weight in a hurry, you might like to know that cutting 500 calories each day from your calculated calorie requirement above will result in an additional weight loss of 0.5 kilos over a week – and cutting 1,000 calories a day will lose an extra kilo a week. However, this would probably be a pretty horrid regime to follow. I am definitely too cranky to even attempt something as crazy as that – so I won’t. It’s hard enough that life often seems like a constant battle between the love of good food and not getting fatter, especially as I stretch my legs out under a comfortable dinner table.
Next: Details of a simple but unambitious diet based on known scientific facts.